---
title: 'Highlight'
sidebar:
  order: 4
  title: Highlight
---

Storybook's Highlight feature is a helpful tool for visually debugging your components. It allows you to highlight specific DOM nodes within your story when used directly or enhancing addons such as the [Accessibility addon](../writing-tests/accessibility-testing.mdx) to inform you of accessibility issues within your components.

![Story with highlighted elements](../_assets/essentials/highlight.png)

## Highlighting DOM Elements

To highlight DOM elements with the feature, you'll need to emit the `HIGHLIGHT` event from within a story or an addon. The event payload must contain a `selectors` property assigned to an array of selectors matching the elements you want to highlight. For example:

{/* prettier-ignore-start */}

<CodeSnippets path="component-story-highlight.md" />

{/* prettier-ignore-end */}

<Callout variant="info" icon="💡">
  We recommend choosing the most specific selector possible to avoid highlighting elements other addons use. This is because the feature tries to match selectors against the entire DOM tree.
</Callout>

### Customize style

By default, highlighted elements contain a standard outline style applied to the selected elements. However, you can enable your custom style by extending the payload object with additional properties to customize the appearance of the highlighted elements. For example:

{/* prettier-ignore-start */}

<CodeSnippets path="highlight-custom-style.md" />

{/* prettier-ignore-end */}

<Callout variant="info">
  These properties are optional, and you can use them to customize the appearance of the highlighted elements. The `hoverStyles` and `focusStyles` properties are recommended for use with the `menu` property. Pseudo-classes and pseudo-elements are not supported.
</Callout>

### Highlight menu

The Highlight feature includes a built-in debugging option, allowing you to select the highlighted elements when you click them. This is particularly useful for inspecting the elements affected by the feature, as it lets you preview a list of elements matching the selector you provided. To enable it, add a `menu` property in the payload object containing additional information about the elements or trigger actions. Each item must include an `id` and a `title`, and you can also provide an optional `selectors` property to limit the menu item to specific highlighted elements.

![Menu with custom items](../_assets/essentials/highlight-menu.png)

{/* prettier-ignore-start */}

<CodeSnippets path="highlight-menu.md" />

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When enabled, the menu will be displayed when you click on the selected element matching your provided selectors. However, if you don't want to show any information, you can omit the items or set the `menu` property to an empty array to show the default menu.

![Menu of selectable targets](../_assets/essentials/highlight-selectable.png)

## Remove highlights

If you need to remove a highlight from a specific element, you can do so by emitting the `REMOVE_HIGHLIGHT` event and providing the `id` of the highlight you want to remove. For example:

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<CodeSnippets path="highlight-remove.md" />

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<Callout variant="info">
  The `emit` function derived from the `useChannel` API hook creates a communication channel in Storybook's UI to listen for events and update the UI accordingly. The Highlight feature uses this channel to listen to custom events and update the highlighted elements (if any) accordingly.
</Callout>

## Reset highlighted elements

Out of the box, Storybook automatically removes highlighted elements when transitioning between stories. However, if you need to clear them manually, you can emit the `RESET_HIGHLIGHT` event from within a story or an addon. This removes all highlights, even ones created by other addons. For example:

{/* prettier-ignore-start */}

<CodeSnippets path="highlight-reset.md" />

{/* prettier-ignore-end */}

## Scroll element into view

The Highlight feature allows you to scroll an element into view and highlight it. To enable it, emit the `SCROLL_INTO_VIEW` event from within a story or an addon. The event payload must contain a `selector` property to target the element you want to scroll into view. When the element is visible, it will be highlighted for a brief moment.

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<CodeSnippets path="highlight-scroll-into-view.md" />

{/* prettier-ignore-end */}

## API

### Parameters

This feature contributes the following [parameters](../writing-stories/parameters.mdx) to Storybook, under the `highlight` namespace:

#### `disable`

Type: `boolean`

Disable this feature's behavior. If you wish to turn off this feature for the entire Storybook, you should [do so in your main configuration file](./index.mdx#disabling-features).

This parameter is most useful to allow overriding at more specific levels. For example, if this parameter is set to `true` at the project level, it could be re-enabled by setting it to `false` at the meta (component) or story level.

### Exports

This feature contributes the following exports to Storybook:

```js
import { HIGHLIGHT, REMOVE_HIGHLIGHT, RESET_HIGHLIGHT, SCROLL_INTO_VIEW } from 'storybook/highlight';
```

#### `HIGHLIGHT`

An event to highlight DOM elements. The event payload must contain a `selectors` property assigned to an array of selectors matching the elements you want to highlight. It can be extended with an optional object containing additional configuration options. See the [usage example](#highlighting-dom-elements) above.

```ts
import { HIGHLIGHT, type HighlightOptions } from 'storybook/highlight';

channel.emit(
  HIGHLIGHT,
  options // The available configuration options inheriting from the HighlightOptions API
);
```

The `options` object contains the following properties:

```ts
interface HighlightOptions {
  /** Unique identifier for the highlight, required if you want to remove the highlight later */
  id?: string;
  /** HTML selectors of the elements */
  selectors: string[];
  /** Priority of the highlight, higher takes precedence, defaults to 0 */
  priority?: number;
  /** CSS styles to apply to the highlight */
  styles?: Record<string, string>;
  /** CSS styles to apply to the highlight when it is hovered */
  hoverStyles?: Record<string, string>;
  /** CSS styles to apply to the highlight when it is focused or selected */
  focusStyles?: Record<string, string>;
  /** Keyframes required for animations */
  keyframes?: string;
  /** Groups of menu items to show when the highlight is selected */
  menu?: HighlightMenuItem[][];
}

interface HighlightMenuItem {
  /** Unique identifier for the menu item */
  id: string;
  /** Title of the menu item */
  title: string;
  /** Description of the menu item */
  description?: string;
  /** Icon for the menu item, left side */
  iconLeft?: "chevronLeft" | "chevronRight" | "info" | "shareAlt";
  /** Icon for the menu item, right side */
  iconRight?: "chevronLeft" | "chevronRight" | "info" | "shareAlt";
  /** Name for a channel event to trigger when the menu item is clicked */
  clickEvent?: string;
  /** HTML selectors for which this menu item should show (subset of HighlightOptions['selectors']) */
  selectors?: HighlightOptions['selectors'];
}
```

Menu items can specify a `clickEvent` to be emitted on the channel when the item is clicked. The channel event will receive two arguments: the menu item `id` and a `ClickEventDetails` object with the following properties:

```ts
interface ClickEventDetails {
  // Position and dimensions of the element on the page
  top: number;
  left: number;
  width: number;
  height: number;
  // Selector(s) which matched the element
  selectors: string[];
  // DOM element details
  element: {
    attributes: Record<string, string>;
    localName: string;
    tagName: string;
    outerHTML: string;
  };
}
```

To listen for this event (assuming `clickEvent: 'MY_CLICK_EVENT'`):

```ts
import type { ClickEventDetails } from 'storybook/highlight';

const handleClickEvent = (itemId: string, details: ClickEventDetails) => {
  // Handle the menu item click event
}

// When you have a channel instance:
channel.on('MY_CLICK_EVENT', handleClickEvent)

// Or from a decorator:
useChannel({
  MY_CLICK_EVENT: handleClickEvent,
}, [handleClickEvent])
```

#### `REMOVE_HIGHLIGHT`

An event that removes a previously created highlight. The event payload must contain an `id` property assigned to the id of the highlight you want to remove. See the [usage example](#remove-highlights) above.

```ts
import { REMOVE_HIGHLIGHT } from 'storybook/highlight';

channel.emit(
  REMOVE_HIGHLIGHT,
  id // The id of the previously created highlight to be removed
);
```

#### `RESET_HIGHLIGHT`

An event to clear all highlights from highlighted elements. See the [usage example](#reset-highlighted-elements) above.

```ts
import { RESET_HIGHLIGHT } from 'storybook/highlight';

channel.emit(RESET_HIGHLIGHT);
```

#### `SCROLL_INTO_VIEW`

An event to scroll a DOM element into view and briefly highlight it. The event payload must contain a selector property assigned to the selector of the element you want to scroll into view. Optionally, you can provide a [`options`](https://developer.mozilla.org/en-US/docs/Web/API/Element/scrollIntoView#scrollintoviewoptions) object to customize the scroll behavior. See the [usage example](#scroll-element-into-view) above.

```ts
import { SCROLL_INTO_VIEW } from 'storybook/highlight';

channel.emit(
  SCROLL_INTO_VIEW,
  selector // Element selector to scroll into view
  options // An object inheriting from ScrollIntoViewOptions API to customize the scroll behavior
);
```
